Below is what
I believe to be a fairly comprehensive -- and growing -- list
of modern voltage regulators, CCS's (constant-current sources)
and power-supply designs. These high-performance designs are intended
to be used for hi-fi audio and have been posted on myriad private and
commercial web sites and Internet forums.

Please
note: I do not sell products nor do I offer kits. Most
of the "[products for sale]", noted below, are known to me
only through web pages and forum group discussions. I only list
commercial-product web sites to show you examples of specific designs
or design execution. I have
not purchased nor built most commercial products. Hence, I cannot
confirm/deny the performance or reputation of any product. As a DIYer,
I would encourage you to: (a) learn as much as you can about these regulators;
(b) build some of the simpler designs; and (c) if you are pleased with
your results, try building one of the more challenging projects. Purchase
ready-made products only as a last resort.

Tangentsoft's
Power Supply Parameter Estimator -- According to Tangent,
this tool "estimates
the voltages in a linear regulated power supply, and then calculates
the heat produced from that. This allows you to iteratively work
out the best power source and heat sink for your power supply."

Capacitors (filter, bypass)

Low ESR (Equivalent Series Resistance): low and medium power: Panasonic
FC and FM, ELNA CERAFINE and Nichicon are capacitor brands to consider;
electrolytic caps show increasing impedance at high frequencies (e.g.
above 10kHz), so it is a good idea to parallel the electrolytic with
film caps.

Snubbers and Dampers

Snubbers: calculate
best snubber values first for resistor, Rs,
and capacitor, Cs. Install on power transformer secondary.

Damper: Install between transformer secondary (AC) and rectifier bridge
and between bridge (and main and main regulator. Use low-value / high
power resistor (0.5 to 5.0 ohms). Carbon best because of very little
inductance (do not use wirewound). Power rating based on particular
current and resistance value: P=I2R

Voltage
regulators for line level circuits [discussion
thread on diyaudio.com on Jung-type
regulators. This thread begins with original POOGE and Jung article
schematic images from 1995 and 2000 Audio Electronics articles.]

(Per-Anders)
Sjöström "Super Regulator", based on Jung's Super
Regulator [products for sale; but site offers complete schematics
and PC boards only]. As Per-Anders notes, his designs are not any
significant topological departure from Jung; rather, they are ergonomically-sized
(layed out) based on compact SMD or through-hole components.

Differences between Series and Shunt regulators: Shunt
regs aren't as efficient as series
regs since they draw their maximum set
current all
the time (regulator circuitry quiescent current + load current
+ shunt device quiescent current) and they will run warm. The
front-end power supply must be able to keep up with continuous-current
demands of shunt regs. The advantage of shunt regs: better supply-line
noise rejection (compared to series regulators) because the error
amplifier regulates it's own supply. Series regs are more
efficient than the shunt regs because they only draw the
regulator circuitry's quiescent current
plus the load current requirements.

TeddyReg (a
compact, series-type DIY regulator; they may be adapted
to a drop-in three-terminal design). Not meant for high-speed applications,
such as digital clocks and clock-regulators, due to very long time-constants
involved in the filtering. This regulator's output impedance varies
with the current drawn; hence, it may or may not suit every purpose.
It can can work decently for circuits, like certain pre-amp blocks,
that are close to constant-current operation -- but, possibly less
successfully for opamp-based circuits.

Constant Current Sources (CCS)

Paul
Hynes CCCS -- a "high-power [cascode] current-source
module [which] has been designed for precision constant current source
applications requiring high impedance over a wide bandwidth" [products
for sale]

PDK Shunt Regulator (uses
CCS: The PDK Shunt regulator is a basic opamp-shunt using: (1) a three-terminal
device as a constant-current source, (2) an opamp with a voltage reference
for control, and (3) a power transistor as the sink device.)

Notes

The flea didn't really start with the overall topology considered,
but from
the other end - the thought that in a regulator, for very small load
currents only, the error amplifier could provide all the output current
required. Using modern high performance op-amps could give exceptionally
low
output impedance across the audio band, exceptionally low noise - and
wide
bandwidth. So the flea started from there as a low-cost diy circuit
that could be worth investigating.

Adding support circuitry to make it work at all owes much to the Sulzer
reg
in terms of keeping raw PSU noise out of the error amp and voltage
reference, without the elaboration of Walt Jung's development of Mike
Sulzer
/ Jan Didden's work.

The flea idea can be made to work as a shunt regulator rather well,
but since its
a bad idea to have high dissipation in the opamp, we stuck with a standard
series regulator layout.